506. Furans. Part II. Friedel–Crafts acylation of furan, 2-methylfuran, and 3-methylfuran

Abstract

By P. A. FINAN and G. A. FOTHERGILL.Furan, 2-methylfuran, and 3-methylfuran with isovaleric anhydride under Priedel-Crafts conditions give the a-isovalerylfurans. The last of these (I ; K = H, R' = Me) was identical with elsholtzia ketone. 2-Acetyl-3-methylfuran (111) and 2-acetyl-4-methylfuran (V; R = Me) were prepared by unambiguous routes ; the product obtained by acetylation of 3-methylfuran under Friedel-Crafts conditions was identical with the ketone (111), and contained no trace of the isomer (V; R = Me).EISHOLTZIA KETONE, found in the essential oils of Elsholtzia cristata Willd. ,2 Perilla .frictescens Brit.: and in Elsholtzia oldhami Heinsl.,* has structure (I; R = H, R' = Me), 011 the basis of degradative5 and synthetic work.6 The tedious nature of the latter prompted us to attempt a synthesis by a Friedel-Crafts reaction on 3-methylfuran, an approach which had been successful for the synthesis of the corresponding dehydrocompound, naginata ketone.Treatment of furan with isovaleryl chloride in the presence of boron trifluoride in ether gave 2-isovalerylfuran (I; I 3 = R' = H) in 10% yield. When isovaleric anhydride was used the yield of ketone was increased to 55% (all yields are based on the anhydride). Similarly 2-methylfuran and isovaleryl chloride gave 2-isovaleryl-5-methylfuran (I ; R = Me, R' = H) in only 15% yield whereas use of isovaleric anhydride gave a 30:/, yield of

Novel inhibitors of poly(ADP-ribose) synthetase

“…3-Acetamidobenzamide and 3-succinylaminobenzamide [3-(3-carboxypropionyl)aminobenzamidel were prepared from 3aminobenzamide and the corresponding acid anhydride. 3-Bromobenzamide was prepared from the acid chloride and ammonium acetate in acetone (Finan & Fothergill, 1961), and 3-hydroxybenzamide from 3-cyanophenol by treatment with slightly alkaline H202 by the method of Radziszewski (1885). Isolation of nuclei and extraction of poly(ADPribose) synthetase Nuclei were isolated from thymus of a freshly slaughtered pig as described by Khan & Shall (1976).…”

2‐(Guanidiniocarbonyl)furans as a New Class of Potential Anion Hosts: Synthesis and First Binding Studies

“…[10,11] Chloromethylation of commercially available methyl furan-2-carboxylate (6) with paraformaldehyde, zinc chloride and anhydrous hydrogen chlo-ride yielded 7. The chloro substituent was replaced according to a literature procedure [12,13] to obtain 8 by heating 7 with anhydrous sodium acetate in acetic acid containing acetic anhydride. The selective hydrolysis of the acetic acid ester group of 8 by reaction with NaOMe in methanol solution gave the furfuryl alcohol 9.…”

“…The selective hydrolysis of the acetic acid ester group of 8 by reaction with NaOMe in methanol solution gave the furfuryl alcohol 9. [13] For the subsequent oxidation step, we first tested a literature procedure [14] reported for a related 2,5-substituted furfuryl alcohol: a two-step oxidation with MnO 2 in acetone with the corresponding aldehyde as an intermediate. During the first step of this reaction, we detected decomposition of the furan compound by TLC.…”

“…The pH values were measured with a Knick pH meter 766 Calimatic at 25°C. 1 H and 13 C NMR spectra were recorded with a Bruker Avance 400 spectrometer. The chemical shifts are reported relative to the deuteriated solvents.…”

Quinolone analogues 7 [1-6]. Synthesis of 3-Heteroaryl-1-methylpyridazino[3,4-b]quinoxalin-4(1H)-ones

“…The reaction of the quinoxaline N-oxide 7 with thiophene-3-carbaldehyde gave the hydrazone 8a, whose reaction with 2-chloroacrylonitrile afforded the 3- compound 6b with acetic anhydride/zinc chloride gave the 3-(5-acetyl-2-furyl)pyridazino [3,4-b]quinoxalin-4(1H)-one 6d in poor yield [13][14][15], while the reaction of compound 6c with N-bromosuccinimide afforded the 3-(5-bromo-2-thienyl)pyridazino [3,4-b]quinoxalin-4(1H)-one 6e [16][17][18]. Screening tests of compounds 6a-e are now in progress, and the screening data will be reported elsewhere.…”